Embodiments of the invention relate to the generation of high frequency clock signals. Clock signals are used in data sampling systems. Clock signals drive analog to digital (ADC) and digital to analog converter (DAC). The performance of the clock signals limits the performance of the ADC and DAC in their dynamically range and spurious performance. Radio frequency (RF) transmission systems require high quality clock signal for the up and down conversion of the baseband signals to and from the RF frequencies. The quality and accuracy of the clock signals effects the overall system performance. In the case of up and down conversion, inadequate clock signals will have a negative impact on the noise, inter-symbol interference and inter-carrier interference. Another embodiment of the invention is the energy efficient generation of clock signals for digital systems.
There are many know devices for the generation high frequency clock signals. Feedback oscillators or negative resistance oscillator. Hartley, Colpitts, Clapp, delay line, phase-shift oscillators standing wave oscillators and rotary traveling wave oscillators are just a view of the many topologies known today. FIG. 1a shows the basic schematic of a rotary traveling wave oscillator. FIG. 1b shows the active devices used to initiate and sustain oscillation.